Furnace, stove, or fireplace.



No. 647,552. Patented Apr. a7., |900.

c. H. BENNETT.

FUBNAGE, STOVE7 0R FIIEPLAGE.

(Application led Feb. 25, 1899,) (N0 Model.)

THE mams Pmns Co.. mogumo.. wAsnmamN. u. c.

, the heat communicated to the grate bar or UNITED STATES i PATENTOFFICE.

CHARLES H. BENNETT, OF LOS ANGELES, CALIFORNIA.

yi-SLJRNACE, sTovE, 0R FiRPLACi-z.

sP'E'oIFmA'rio forming part of Letters Patent No. 647,552, dated Api-i117, 190e.

Application filed February 2 5, 1 89 9.

To @ZZ whom t may cortcerm.

Be it known that I, CHARLES H. BENNETT, a citizen of the United States,and a resident of the city of Los Angeles, in the county of Los Angelesand State of California, have invented certain new and usefulImprovements in Furnaces, Stoves, or Fireplaces, of which the followingis a specification.

One of the principal objects of my invention is to obtain a downdraftthrough the burning fuel, and thus to more perfectly consume the fuel.The tendency in combustion where the fuel is fed or thrown onto the firefrom above is'tocause the lower portion of the fuel to be incandescent.That portion of the fuel which is above is caused to throw 0E itsvolatile products of combustion. Where the draft of air fed to the fuelenters below the fuel and passes up through the latter, the incandescentvolatile products of combustion from the superincumbent freshlyaddedfuel pass up and away from the fire and much of lthem (especially inbituminous coal) are not consumed, but pass out of the chimney in theform of smoke. In such escaping products there also passes a quantity ofunconsumed carbon. The waste therefore is apparent.

By my invention the products of combustion--gases, carbon, and thelike-escaping from the coal at the top of the lire are carried down intocontact with the incandescent fuel by the downdraft of air and are therethoroughly consumed.

Another object of my invention is such a construction of one or moregrate-bars for su pporting this fuel as shall enable the gratebars to bekept cool, and therefore prevent these bars from being melted or burnedout by the heat of the fire being carried down against them and pastthem by the downdraft aforementioned.

Another object of my invention is to utilize bars by heating air, whichmay be carried to any place where the hot air is needed.

The several features of my invention and the various advantagesresulting from its use, conjointly or otherwise, will be fully apparentfrom the following description and claim.

In the accompanying drawings, making a part of this application, similarletters of ref# erence indicate corresponding parts.

My invention is applicable to various kinds of furnaces, stoves, andgrates..

Inasmuch as the invention is thoroughly illustrated by showing it asapplied to a warme air furnace, I have in the drawings shown one kind ofwarmeair furnace and the application of my invention thereto.

In the drawings, Figure l is a front 'perL spective view of a warm-airfurnace to which my invention has been applied. Fig. 2 represents avertical central section ofthe fur nace, taken in the plane of thedotted line 2 2 of Fig. l. In this View a part of therear portion of thefurnace unnecessary to the comprehension of my invention and containingmerely a hot-air space is broken out and removed and the rear end of thefurnace brought forward, as shown. The object of this condensation is toeconomize space on` the sheet of drawings. Fig. 3 represents a portionof a vertical central section of a porL tion of the side eXit-flues.This section is taken in the plane of the dotted line 3 3 of Fig. 4..Fig t is a vertical central transverse section of the furnace, taken inthe plane of the dotted line 4t i of Fig. 2. Fig. 5 is a plan view ofthe grate-bars and of those portions of the furnace-wall and of itsprojections which are in the immediate vicinity of these bars.

The outer enveloping shell or casing A is to be of any desired shape. Ator near the bottom thereof is a suitable cold-air inlet to admit coldair to be heated for useful and well-known purposes. `Within thiscasing, but separated therefrom at a sufficient distance to allow hotair heated by the furnace to freely rise is the furnace B itself. Inthis furnace C is the fire-pot, composed of the lower division C3 andthe upper division O2. The upper division has the inlet feed-passage C4,closed by the usual door C5.A Air to feed the `fire and to create adraft regulated by a suitable door is admitted through a suitableopening in the feed-door. This opening is located above the point wherethe charge of fuel comes when the furnace is properly filled. In thepresent illustrative instance the air-inlet'IB is in and through anopening in the door C5, and this inlet-passage is con` IOO trolled by adoor IB2. At the upper portion of the furnace is the exit smoke-nue O6.Inasmuch as the usual course of the waste products of combustion-smoke,&c.-is downward through the furnace, this exit-flue C6 is usually closedby a draft-damper C7. This door may be operated by a rod C8 orotherwise.

Suitable provision is made to receive the waste products of combustionafter they pass down through the grate and into the ash-pit. A practicaland novel provision for this purpose is shown and consists as follows,viz: .This provision is in duplicate, there being one such on each sideof the ash-pit and furnace. Adescription of one will suiice for both,viz: In the side of the ash-pit D is an opening E, and this connectswith an exit-flue F, which is arranged so as to curve back and forthwithin the casing A. Thus it (this iiue) is enabled to come into contactwith a large amount of air and to transmit its heat to the latter. Theexit end of this flue F connects with `the exit passage or chamber G, inturn connecting with an exit-hue G2. It is to be noted that the upperend of the furnace through the exit C6 does, when the flue-door is open,connect with such passage or chamber. The several windings or branchesof the iiue F are respectively represented by the characters F2, F3, F4,and F5.

I will now proceed to describe the means for sustaining the fuel in thefurnace. I provide one or more grate-bars H. These are not commongrate-bars, but ones that are tubular. Solid grate-bars would soon burnout for the reason that a downdraft carries the flame and heat intoconstant direct contact with the bars after the manner of the blowpipe,and the ordinary bars would soon warp and melt under the intense heat towhich they are necessarily subjected. Through each of these tubulargrate-bars H, I pass a rapidly-moving current of air, and the air thuspassed takes the heat of the grate-bars, and thus highly heated passesinto the space S between the casing A and the furnace B and is conductedthence ordinarily to be used along with the other heated air of thefurnace. l

I am aware that water has been passed through ordinary tubes to keep thelatter cool while used as grate-bars in steam-boilers. I employ airinstead of water, inasmuch as water cannot be always obtained withoutexpense and its use in such connection would entail the attendance of anoperator to operate it and is, in fact, wholly impracticable in such afurnace.

I obtain in the use of air means for cooling the grate which are veryeconomical and entirely practicable. In addition to providing aconstruction wherein tubular grate-bars and means for enabling air topass through them are present, which construction and means constituteone feature of my invention, I-have invented the following novelconstruction of der to pass the air through at a proper speed, I mustprovide for the expansion of the air during the operation of heating it.This is done by flaring or tapering the hollow gratebar. I cause theamount of flare to be proportionate to the intensity of the heat towhich the grate-bars will ordinarily be subjected, because the degree ofexpansion of the air as it passes through the grate-bars will dependupon the amount of heat which it receives. Thus the are of the tubularspace within the grate-bar will rightly accommodate the moving air inthe course of its expansion as it passes within' and through thegrate-bars. While the roof and floor of the space within the grate-barmay each incline, the one upward and the other downward from thehorizontal, or the roof maybe horizontal while the floorinclinesdownward, yet the preferred directions of the Hoor and roof are asshown. I have thus inventively located them (see Fig. 2) in order to thebetter enable them to carry into effect the purposes of my invention.Therefore I have located the floor H2 in a horizontal plane and the roofH3 of the gratebar in a plane inclined to the horizontal. Thus where thetubular space of the bar has a given iiare the angle of the inclinationto the horizontal will be greater than where the iloor inclines downfrom the horizontal. This great inclination of the roof possesses agreat advantage, to wit: It allows the heated air a good opportunity toeasily pass off through and from the tubular passage PH of the gratebarin a natural rising current. Such an inclination of the roof of thistubular passage does not necessitate any further thickening of thegrate-bar in the neighborhood of the inlet end I of the passage PHthrough it, because by locating the inlet ends of the bars- Viz. at thatside of the furnace opposite where the feed-door is locatedas I haveshown the inclination of the tops of the bars is downward from thedoors, and this is an advantage, as it enables the fuel to be wellhandled lOO IIO

by the poker and causes the fuel to bank in a position where it can bereadily reached by draw-bar or poker operated through the feeddoor.

In order to increase the capacity of the gratebars for transmitting heatto the air passing through them, (whenever such increased capacity isneeded,) I provide within this bar a ange or flanges or projections FH,which extend into the tubular space of the bar and transmit heat fromthe latter to the air contained within. In other Words, I increase thesurface of the grate-bar which comes in contact with the air movingthrough it. Thus I transmit the heat more rapidly to the air and heatthe latter more rapidly, increase the speed with which it (the air)passes through the grate-bars, and am thereby enabled to heat the airfrom this source more quickly and at the same time keep the grate-barscooler and in a condition wherein they are but the lire-grate barsthemselves, to wit: In orlittle liable to be injured from the heat incontact with their exterior surface. The shape of these bars and their(interior) spaces in cross-section may be varied as desired. A preferredshape thereof is shown in Fig. A, where the grate-bars and the tubularpassage are alike heart-shaped, the narrower or pointed portion beingbelow. Such a shape confers upon the grate bar great resistive strengthin a vertical direction. This is the direction-viz., from abovedownward--in which the greatest pressure is exerted upon the grate-bars.The bottom of the bars being narrow affords the ashes falling betweenadjacent bars or between the bars and the adjacent sides of the fire-potbetter opportunity to pass down and leave these spaces clear for thepassage of the downdraft through them.

It is to be understood that the application of my invention is not to belimited to any special shape of fire-pot or those other accompanyingportions of the furnace which are old, well known, and are to be foundin many shapes and forms in common use.

The downdraft, irrespective of the particular shape of the grate-barsaforementioned, keeps the fire substantially clear of ashes, as thedraft carries the latter down between the grate-bars into the ash-pit.

The mode in which my invention operates is as follows: The fuel isplaced upon the grate-bars H and lighted. The upper exit or door C7 inthe roof of the fire-pot is opened until the fire has become thoroughlykindled. This door C7 is then closed and the air entering through theinlet-port IB of the door C5..

passes down through the fuel and between the grate-bars, and thence downand through the passage E into the `Iiues F and rising passes throughthese flues F into the exit flue or chamber G, and thence out throughthe exit-flue G2. By these means the fiues F, dto., are heated andtransmit their heat to the air within the casing A in the usual manner.This heated air is, as customary, conveyed to the place or places whereit is needed. The grate-bars soon become heated and transmit their heatto the air within them. This air expands and moves through the tubularspace PH of each grate-bar H and out of the enlarged end thereof andpasses upward into the space between the furnace and casing and goespast the feed inlet-passage C4, as shown in Fig. 6, and adds to the hotair, (aforementioned,) which is to be conveyed to the point or pointswhere needed. Meanwhile the cold air entering the inlet end of thetubular bars H, preferably by means of an introductory tube IH, passesinto and through said gratebars and keeps the latter at a comparativelylow temperature by withdrawing heat from the bars and conveying itonward, as aforementioned. On the drawings arrows duly indicate therespective directions of the various aforementioned currents of air.

From the foregoing description of the construction and mode of operationof my invention it is believed that the latter will be readilyunderstood.

Where the fire-pot C3 is circular or oval in the planes of thegrate-bars, a frill or other suitable projection or projections G9 maybe present to partially fill the space between the inner side of the potand the adjacent gratebar, substantially as shown.

To enable those not fully skilled in the art to understand the use ofcertain parts not heretofore described and forming no part of myinvention, I here specify that the doors F6 (indicated in Figs. l and 4)give access to the branches F2, F3, F4, and F5 of the iiues F, so thatthe latter may be inspected, cleaned, and repaired.

D2 indicates the usual door of the ash-pit,

' through which access may be had to the ashpit and to the under side ofthe fire-grate bars.

My invention is especially applicable to furnaces; but, as heretoforeindicated, my invention is applicable not only to furnaces but also tothe fireplaces of stoves and other fireplaces.

What I claim as new and of my invention, and desire to secure by LettersPatent, isV

In a furnace or the like, a fire-pot, feeddoor, and inlet, and thegrate-bars H, hav- 95 ing passages PH through them, inlet-ports to thesepassages, the latter Haring, as they approach their outlet, the bottomof the bars lying in a horizontal plane', and their tops inclined,substantially as and for the purposes rco specified.

CHARLES H. BENNETT.

Attest:

OHAs. M. LESLIE, K. SMITH.

